| OHD | hydroxyvitamin D; Office of Human Development; Ondine-Hirschsprung disease; organic heart disease |
|---|---|
| OIT | organic integrity test |
| OMD | ocular muscle dystrophy; oculomandibulodyscephaly; organic mental disorder; oromandibular dystonia |
| OMS | organic mental syndrome; otomandibular syndrome |
| Org, org | organic |